Seung Sik Choi

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—Wireless sensor networks consist of sensor nodes which are expected to be battery-powered and are hard to replace or recharge. Thus, reducing the energy consumption of sensor nodes is an important design consideration in wireless sensor networks. For the implementation of an energy-efficient MAC protocol, a Sensor-MAC based on the IEEE 802.11 protocol,(More)
We demonstrated extraordinary THz transmission through ring apertures on a metal film. Transmission of 60% was obtained with an aperture-to-area ratio of only 1.4%. We show that the high transmission can be suppressed by over 18 dB with a thin layer of free carriers in the silicon substrate underneath the metal film. This result suggests that(More)
We developed a reliable mobile Peer-to-Peer (P2P) data sharing system and performed some experiments for verifying our routing scheme using our real testbed. Our method for guaranteeing reliable P2P data sharing mainly deals with the problem of disconnection due to the sudden disappearance of one or more nodes involved in the active transmission route. The(More)